Counterbalanced window operator

Abstract: A counterbalanced window operator includes a housing in which a rotatable lead screw (5) rotated by a crank handle (6) or an electric power unit (11), cooperates with a non-rotatable nut member (4) to axially displace the nut member and move pivoting arms (2,3) to open and close the window.

Description: The present invention relates to a window having a main frame, particularly a rectangular main frame, and a sash, particularly a rectangular sash, mounted for pivoting movement relative to the main frame about a pivot axis substantially parallel to a pair of opposed sides of said sash, in combination with a window operator for opening and closing said sash with respect to said main frame, the operator comprising at least one arm connected in a first end with one of said opposed sides of the sash and mounted for pivoting about a pivot point which is stationary with respect to said main frame and means for moving said arm about the pivot point, said moving means comprising a rotatable elongate screw member journaled for rotation and having an axis which is arrestable with respect to said main frame, means for preventing axial displacement of said screw member with respect to said main frame, and a non-rotatable nut member operatively connected through a link member with said arm at a point intermediate said first and second ends thereof and engaged by said screw member to be axially displaced by said screw member upon rotation of said screw member, whereby to cause said arm to pivot about said pivot point, said link member comprising a first arm member rigidly connected with said nut member and a second arm member, one end of which is linked for pivotal connection with said first arm member, whereas the other end of said second arm member is linked for pivotal connection with said at least one arm. Operators for opening and closing such windows or similar devices are known, e.g. from AU-B-428 047, and may be used for moving the window between closed and open positions. When used in combination with a window such as a window having a stationary main frame mounted in a roof of a house or other building, especially a sloped roof, and a sash hinged to the main frame at the top of the sash for pivoting toward and away from the main frame, such operators are typically mounted on a bottom member of the main frame and connected to a bottom member of the sash for pushing the sash away from the main frame and drawing the sash into engagement with the main frame. When the window operator is actuated, in such an installation, to move the window in an opening direction, it must overcome a component of the weight of the window, especially when the window is mounted in a roof. In order to overcome this difficulty, counterbalancing devices employing springs have been provided to counteract the weight component of the window and, thereby, reduce the force which must be applied to the operator, either by hand or by a power unit. Counterbalanced window operators to this effect are disclosed in US-A-5,097,629 and US-A-2,698,173. In the prior art operator construction defined above and known from AU-B-428047 the operator arm is slidably connected with a track forming member extending at right angles to the pivot axis of a caravan hatch cover to be operated and pivotally connected at one end with a point which is stationary with respect to the operator housing and is engaged at the other end with the nut member of the moving means through a link arm so that during the opening and closing movement the operator arm moves in a plane perpendicular to the pivot axis. In a top-hinged window construction of the kind described, the operator arm is connected with the bottom member during the opening and closing movement and moves generally in a plane parallel to the pivot axis of the window and must be arranged to follow the circular movement of tea bottom sash member of the window around the pivot axis of the window. It is the object of the invention to provide a window of the kind defined allowing such movement of the operator arm and, at the same time, allowing for arrangement of counterbalancing means with an operator of a very compact design of high stability and functional reliability so that the moving means of the operator may be completely accommodated in a fairly small housing mounted on tea bottom of the main frame. According to the invention this is accomplished by a window of the kind defined which is characterized in that said pivotal connections are provided by link means permitting movement of said at least one arm about a further axis substantially perpendicular to the axis of said screw member, and that means is provided for adjusting the axis of said screw member with respect to said main frame in a plane perpendicular to said further axis, counterbalancing means being operatively connected between said main frame and said arm for counteracting a weight component of the window. By this arrangement of the pivotal connections of the link member and by arranging the screw member to have its axis adjustable with respect to the main frame the construction according to the present invention offers the advantage that with a very compact design of high stability and functional reliability the operator mechanism will allow the arm or arms connected with the bottom sash member to freely follow the circular movement of the latter. In the following the invention will be further explained with reference to the accompanying schematical drawings in which Fig.1 is a schematic view of a window operator for a window; Fig. 2 is a side schematic view of the operator mechanism of a window operator for a window according to the present invention; Fig. 3 is a cross section of a portion of a window sash with which an operator arm of the mechanism shown in fig. 2 is connected; Fig. 4 is a perspective view of an electric drive unit for the window operator. In the window shown schematically in fig. 1 a connection between a sash and an operator housing 11, which is mounted, e.g., at the bottom member of the main frame, is provided by two pivoting arms 12-13, one end of each of which is pivotally journaled about a pivot point in the housing 11. The other end of each pivoting arm is pivotally connected as shown in fig. 3 with a bottom member S of the sash by means of slide shoes 12a-13a, slidably displaceable in the longitudinal direction of said member in tracks of a track member T secured on the bottom member S. The drive member for the opening movement is a non-rotatable nut member 14 engaged by a rotatable lead screw 15 operated by cranking a handle 16. A thrust bearing B2 is provided in the housing 11 to support the lead screw 15 for rotation and to withstand axial forces imposed in the lead screw. The connection between the nut member 14 and the pivotal arms 12-13 is provided by a symmetrical pair of links 17 respectively, having one end pivotally connected with the non-rotatable nut member 14 and another end pivotally connected with the respective arm 12-13 in a point 12b-13b located at some distance from the end of the arm pivotally journaled in the housing 11. A symmetrical arrangement of a counterbalancing spring mechanism is provided to facilitate the opening movement of the window by compensating for the weight of the window. As illustrated, the counterbalancing mechanism may comprise a torsion spring 18 with two fingers 19 each curved around and engaging one of the pivoting arms 12-13, the torsion spring being mounted on a stationary pin 20 in the housing 11. Alternatively, other forms of counterbalancing mechanisms may be used such as a mechanism comprising on each side either a compression spring or a torsion spring such as a coil spring, pivotally connected at one end to the bottom member of the main frame outside the housing 11 and pivotally connected at the opposite end to the above-mentioned respective point 12b-13b at the respective arm 12-13. In Fig. 2 is shown an embodiment of the inventions having an operator mechanism in which links 17b between the non-rotatable nut member 14 and the arms 12, 13 allow the arms 12, 13 to pivot about an axis perpendicular to the axis of the rotatable lead screw 15. The connection between the links 17b and the pivot arms 12, 13 as well as between the links 17b and the non-rotatable nut member 14, comprise spherical joints, or ball-and-socket joints, 17c. Such joints permit the pivot arms 12, 13 to follow the opening movement of the bottom of the sash S as it pivots about the axis of the hinges at the top of the sash by which the sash is mounted on the main frame. The axis of the lead screw 15 is adjustable with respect to the main frame of the window by means of a slide member 20a, which is slidable in a curved slot 20b in a bracket 20c connected to the main frame and arrestable by means of arresting screws 20d. Fig. 4 shows an electric drive unit M which can be connected to the lead screw 5, 15, 25 to drive the lead screw, instead of using the handle 6, 16, 26.

Claims: A window having a main frame, particularly a rectangular main frame, and a sash, particularly a rectangular sash, mounted for pivoting movement relative to the main frame about a pivot axis substantially parallel to a pair of opposed sides of said sash, in combination with a window operator for opening and closing said sash with respect to said main frame, the operator comprising: at least one arm (12,13) connected in a first end with one of said opposed sides of the sash and mounted for pivoting about a pivot point which is stationary with respect to said main frame; and means for moving said arm about the pivot point, said moving means comprising a rotatable elongate screw member (15) journaled for rotation and having an axis which is arrestable with respect to said main frame, means for preventing axial displacement of said screw member (15) with respect to said main frame, and a non-rotatable nut member (14) operatively connected through a link member (17) with said arm (12,13) at a point intermediate said first and second ends thereof and engaged by said screw member (15) to be axially displaced by said screw member upon rotation of said screw member, whereby to cause said arm (12,13) to pivot about said pivot point, said link member (17) comprising a first arm member rigidly connected with said nut member and a second arm member, one end of which is linked for pivotal connection with said first arm member, whereas the other end of said second arm member is linked for pivotal connection with said at least one arm (12,13), characterized in that said pivotal connections are provided by link means (17c) permitting movement of said at least one arm about a further axis substantially perpendicular to the axis of said screw member, and that means (20a-20d) is provided for adjusting the axis of said screw member (15) with respect to said main frame in a plane perpendicular to said further axis, and counterbalancing means being operatively connected between said main frame and said arm for counteracting a weight component of the window. A window as claimed in claim 1, characterized in that said moving means comprises a manually manipulatable member (16) connected to said screw member for manual rotation of said screw member. A window as claimed in claim 1, characterized in that said moving means further comprises an electrically powered drive unit (M) connected to said screw member (15) for rotating said screw member. A window as claimed in claim 1, 2 or 3, characterized in that said first end of said at least one arm (12,13) is adapted for sliding connection with the sash of the window, whereas said pivot point is located at a second end of said arm. A window as claimed in any of claims 1 to 4, characterized in that said screw member (15) comprises a threaded spindle and said nut member (14) comprising a head member with a threaded bore engaged by said spindle. A window as claimed in any of claims 1 to 5, characterized by comprising two of said arms (12,13). A window as claimed in any of claims 1 to 6, characterized in that said counterbalancing means comprises a torsion spring (18) secured about a stationary pin (20) on said main frame, said torsion spring having a finger (19) engaging each said arm (12,13). A window as claimed in any of the preceding claims, characterized in that said link means (17c) comprises spherical joints at both ends of said second arm.

Inventors: CHRISTENSEN PER BJORN, CHRISTENSEN, PER BJORN
Applicants: VELUX IND AS, VELUX INDUSTRI A/S
Application year: 1994
Main classification: E05F11
IPC codes: E05F11, E05F1, E05F15